How to spot a bad cable modem?

I have seen that exactly many times.
Usually you can call the provider and have them test the modem from thier end too.
At the same time tell them his system is fine and no issue's except for when connected to that modem and they usually replace it.

"The Talon prowls the dark recesses of your mind and brings your demons to life."Nascar Fury

How to spot a bad cable modem?

In general, there's no sane way to test the modem short of swapping it.

Short of that, get the manual for the modem, and learn what each of the blinking lights mean -- probably the most important is the one that indicates 'sync' with the cable signal. At the least, you should be able to learn what a normal lights presentation looks like. If the questionable modem can't achieve that, then you *still* don't know if the problem is the modem or the cable company.

For my cable co. [Comcast] they have been willing to come by my house and attach a tester to the cable itself, to check for signal quality. Could be they were more willing since they also sold me my first cable modem [which is likely fine, since a new Motorola Surfboard didn't solve the problem I was having].

In the end, there's no way I know of to distinguish between a problem at the Comcast server from a modem problem, unless they are willing to tell you the truth about it. When I had my problems, I eventually bought a new modem to attempt to prove it wasn't at my location.

How to spot a bad cable modem?

HI back & thanks for confirming. He already had the ISP run a test & they say "all's well" on their end.

+++++++++++++

Ahhhh... to be very very VERY clear, have him tell the cable co. to run a test of the drop from the main cable to his wall outlet. I guess it depends on the exact meaning of "end" -- but it should mean the place inside his house where the modem is attached -- that's the point of sale, so to speak, and in every case I know about, the responsibility of the cable company extends to that last piece of cable, i.e., right up to the modem itself.

The only way to do this correctly is to unscrew the inside cable *at the modem* and attach that cable to their tester device. The signal could be perfectly fine on the main cable on the pole outside, and every other customer on the link might have good service, but one noisy connector between the cable and your friend's modem can kill the signal quality.

How to spot a bad cable modem?

All's well on their end means ha ha ha, you bought your modem and we don't care.

Sad to say, he needs to lease or buy a new one.
I would go for the lease then if he has the problem again get a new one at no cost.

I'm lucky, my ISP doesn't charge for the modem, good thing I'm on #8 after 7 years, first Motorolla lasted for 5 years, then they switched to Toshiba (junk) now they're back to Motorolla, hope this Toshiba breaks soon :)

How to spot a bad cable modem?

I have a wired cable modem (I upgraded to wireless) that I can sell him if he wants it...

He was supposed to try a friend's modem on his line. He called to say it didn't work- I had to tell him he'd need them to key in the new MAC- he didn't know/remember that part- lol. Haven't heard back yet...

How to spot a bad cable modem?

Ok, the most LIKELY issue is that the networking cable is the wrong gender. The WAN connection on a cable modem can either use a passthru or crossover RJ45 cable. There is usually a switch that sets this on the cable modem but sometimes there is not. MAKE SURE you have the right cable attached! If this does not fix it, Get rid of any hubs or routers that are in the way. Next is to make sure that the PC is set to get a DHCP address. Next is to read the modem instructions to get the modems IP address and ping the cable modem in a cmd window. run cmd ping 192.168.0.1 is the usual way. If you are not pinging the modem then you have an issue in communicating to the modem. Last is to have the cable company read back the hardware MAC address that is located on the sticker of the modem. I doubt you have a broken modem.

How to spot a bad cable modem?

I had the guy call Adelphia the next time he could. He said they had him do all of the same things I had done. They assured him all was well & he should be receiving internet- it had to be his PC (around here, they love to have you reformat). Luckily, he remembered to tell them that I had run this tower, here at my house, without any trouble (therefore, not the PC).

After about 30 min. of this, they finally agreed to send someone out to check his line. He shutdown the PC & had dinner. Then, just to give it one more try, booted up- and was online!

So, to summarize- no, it was not the modem. No, it was not the PC. It had to be something on the cable co.'s end but we'll never know what...

How to spot a bad cable modem?

Heh! well, the nice thing is now you know two things: how to troubleshoot a cable modem hookup and to never trust that the cable company knows what they are talking about. The head end of the cable company's rig just had to reset your MAC address.

In fairness tho, I just upgraded my Cox cable based high speed internet and that went smooth as silk. Some old lady behind the counter upgraded the service and added the MAC address of the new router. Guess they are learning.